HADOOP-2421. Fix links to current javadoc to be relative rather than absolute.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/core/trunk@699428 13f79535-47bb-0310-9956-ffa450edef68

build.xml

@@ -902,7 +902,7 @@
          <param name="-oldapidir" value="${jdiff.xml.dir}"/>
          <param name="-newapidir" value="${jdiff.xml.dir}"/>
          <param name="-javadocold" value="${jdiff.stable.javadoc}"/>
-         <param name="-javadocnew" value="${build.javadoc}/"/>
+         <param name="-javadocnew" value="../../api/"/>
          <param name="-stats"/>
        </doclet>
        <classpath >